Temperature-regulator.



UNITED STATES PATENT OFFICE;

WALTER B. DAHL, 0F MINNEAPOLIS, MINNESOTA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO B P. KIMBALL. 0F MINNEAPOLIS. MINNESOTA.

TEMPERATURE-REGULATOR.

Specification of Letters Patent.

Original application filed October 25, 1912, Serial No. 727,716. Divided and this application filed January 21, 1913. Serial No. 743.259.

To all whom it may concern:

Be it known that I, WALTER B. DAHL, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Temperature-Regulators, of which the following is a specification.

My invention relates to new and useful temperature regulators, especially such regulators in which a thermostatic lamina oper ates to make or break an electric circuit when the temperature goes above or falls below a certain point, the said circuit controlling means for opening and closing the drafts of a furnace.

This application is a division of my copending application, Serial Number 727,716.

It is the object of my invention to construct such a lamina in which the different strips of metal forming the same are combined and held together by stamping portions of one strip into and over operations of the other strip, thus avoiding the usual weldmg.

Itis also an object of my invention to provide means carried by the end of the lamina for adjusting the switch plate so that it will make contact at the proper moment relative to the determined temperature, said adjustment being made without changing the position of the contact points, which will be definitely adjusted and fixed at the factory.

The full objects and advantages of my invention will appear in connection with the detailed description thereof and are particularly pointed out in the claims.

In the drawings illustrating the application of my invention in one form, the figure is a plan view of the thermostat having my inventions applied thereto.

As shown inthis drawing, a base plate 10 is provided having thereon a post 11, to which is secured one end of a thermostatic lamina 12 curved in a spiral of the usual form and having a radial extension 13 at its free end. The lamina 12 is formed of two sheets of metal locked together by means of tongues 14, one strip interlocking with and lapping over the other strip.

The

aforesaid radially extended portion 13 has secured thereto at 15 a contact strip 16 which extends between two contact points 17 and 18, which contact points are relatively fixed to a non-conducting member 19 and spaced apart asuitable distance. The radial member 13 is provided with an offset portion 21 within which is threaded a screw 22, the end of said screw bearing against contact strip 16.

It will be apparent that by turning the screw 22, the position of the contact plate 16 may be adjusted relative to contact points 17 and 18 so as to determine the temperature at which contact will be made with one or the other of said contact points. he contact points 17 and 18 are rigidly secured to the plate 19 and will never need adjustment after leaving the factory, all required adjustment of contact plate 16 being effected by means of the screw 22. The plate 16 is, of course, made of spring metal so that the adjustment above described is verv delicate and thoroughly eifective for the purpose. Such an adjustment is very desirable because the distance between the contact points 17 and 18 is necessarily small, and a variation thereof may render the thermostat either inactive or wholly inoperative. It is extremely difiicult to adjust the points relative to the contact bar 16 without varying the distance between the points. \Vith my device, as above stated, no variation in the distance apart of the points ever occurs since that distance is fixed at the factory. The high utility and desirable characteristics of my novel adjusting device will, therefore, be obvious.

I claim:

1. A temperature regulator comprising a lamin secured at one end and freely movable at the other end, a pair of contacts spaced apart, a switch plate carried by the movable end of the lamina and extending between the contacts, and means connected to the end engaging the switch plate at a point outside of the point of connection thereof to the lamina for adjusting the position of said switch plate relatively to the contacts.

2. A temperature regulator comprising a position of the same relatively to the c0nlamina having a rectilinear arm and an tacts. is ofi'set portion on said arm, a pair of con- In testimony whereof I afiix my signature tacts spaced apart, a switch plateriveted to in presence of two Witnesses. the arm of the lamina and extending bet .WALTER B. DAI-IL. tween the contacts, and a screw threaded Witnesses: into the oflset portion of said arm and en- H. A. BOWMAN, gaging said switch plate for adjusting the F. A. WHITELEY. 

